This standard establishes mandatory requirements applicable to Satellite Communications (SATCOM) terminals required to access 5-megahertz (MHz) ultra-high frequency (UHF) SATCOM channels using the Mobile User Objective System (MUOS) Common Air Interface (CAI). Terminals that meet these mandatory requirements are referred to as MUOS Terminals (MT). The code-division multiple-access (CDMA) frame structure, timing requirements, and protocols for accessing overhead and ground segment services are defined herein and represent the minimum requirements that must be implemented. Requirements in this standard may be exceeded by equipment developers to satisfy specific Department of Defense (DoD) requirements, provided interoperability is maintained. For example, the incorporation of additional standard and nonstandard interfaces is not precluded. Chairman Joint Chiefs of Staff Instruction (CJCSI) 6251 complements this standard by defining the processes and requirements necessary to certify an MT for operational use.